diff options
Diffstat (limited to 'drivers/misc/cs5535-mfgpt.c')
| -rw-r--r-- | drivers/misc/cs5535-mfgpt.c | 370 |
1 files changed, 370 insertions, 0 deletions
diff --git a/drivers/misc/cs5535-mfgpt.c b/drivers/misc/cs5535-mfgpt.c new file mode 100644 index 0000000..8110460 --- /dev/null +++ b/drivers/misc/cs5535-mfgpt.c @@ -0,0 +1,370 @@ +/* + * Driver for the CS5535/CS5536 Multi-Function General Purpose Timers (MFGPT) + * + * Copyright (C) 2006, Advanced Micro Devices, Inc. + * Copyright (C) 2007 Andres Salomon <dilinger@debian.org> + * Copyright (C) 2009 Andres Salomon <dilinger@collabora.co.uk> + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of version 2 of the GNU General Public License + * as published by the Free Software Foundation. + * + * The MFGPTs are documented in AMD Geode CS5536 Companion Device Data Book. + */ + +#include <linux/kernel.h> +#include <linux/spinlock.h> +#include <linux/interrupt.h> +#include <linux/module.h> +#include <linux/pci.h> +#include <linux/cs5535.h> + +#define DRV_NAME "cs5535-mfgpt" +#define MFGPT_BAR 2 + +static int mfgpt_reset_timers; +module_param_named(mfgptfix, mfgpt_reset_timers, int, 0644); +MODULE_PARM_DESC(mfgptfix, "Reset the MFGPT timers during init; " + "required by some broken BIOSes (ie, TinyBIOS < 0.99)."); + +struct cs5535_mfgpt_timer { + struct cs5535_mfgpt_chip *chip; + int nr; +}; + +static struct cs5535_mfgpt_chip { + DECLARE_BITMAP(avail, MFGPT_MAX_TIMERS); + resource_size_t base; + + struct pci_dev *pdev; + spinlock_t lock; + int initialized; +} cs5535_mfgpt_chip; + +int cs5535_mfgpt_toggle_event(struct cs5535_mfgpt_timer *timer, int cmp, + int event, int enable) +{ + uint32_t msr, mask, value, dummy; + int shift = (cmp == MFGPT_CMP1) ? 0 : 8; + + if (!timer) { + WARN_ON(1); + return -EIO; + } + + /* + * The register maps for these are described in sections 6.17.1.x of + * the AMD Geode CS5536 Companion Device Data Book. + */ + switch (event) { + case MFGPT_EVENT_RESET: + /* + * XXX: According to the docs, we cannot reset timers above + * 6; that is, resets for 7 and 8 will be ignored. Is this + * a problem? -dilinger + */ + msr = MSR_MFGPT_NR; + mask = 1 << (timer->nr + 24); + break; + + case MFGPT_EVENT_NMI: + msr = MSR_MFGPT_NR; + mask = 1 << (timer->nr + shift); + break; + + case MFGPT_EVENT_IRQ: + msr = MSR_MFGPT_IRQ; + mask = 1 << (timer->nr + shift); + break; + + default: + return -EIO; + } + + rdmsr(msr, value, dummy); + + if (enable) + value |= mask; + else + value &= ~mask; + + wrmsr(msr, value, dummy); + return 0; +} +EXPORT_SYMBOL_GPL(cs5535_mfgpt_toggle_event); + +int cs5535_mfgpt_set_irq(struct cs5535_mfgpt_timer *timer, int cmp, int *irq, + int enable) +{ + uint32_t zsel, lpc, dummy; + int shift; + + if (!timer) { + WARN_ON(1); + return -EIO; + } + + /* + * Unfortunately, MFGPTs come in pairs sharing their IRQ lines. If VSA + * is using the same CMP of the timer's Siamese twin, the IRQ is set to + * 2, and we mustn't use nor change it. + * XXX: Likewise, 2 Linux drivers might clash if the 2nd overwrites the + * IRQ of the 1st. This can only happen if forcing an IRQ, calling this + * with *irq==0 is safe. Currently there _are_ no 2 drivers. + */ + rdmsr(MSR_PIC_ZSEL_LOW, zsel, dummy); + shift = ((cmp == MFGPT_CMP1 ? 0 : 4) + timer->nr % 4) * 4; + if (((zsel >> shift) & 0xF) == 2) + return -EIO; + + /* Choose IRQ: if none supplied, keep IRQ already set or use default */ + if (!*irq) + *irq = (zsel >> shift) & 0xF; + if (!*irq) + *irq = CONFIG_CS5535_MFGPT_DEFAULT_IRQ; + + /* Can't use IRQ if it's 0 (=disabled), 2, or routed to LPC */ + if (*irq < 1 || *irq == 2 || *irq > 15) + return -EIO; + rdmsr(MSR_PIC_IRQM_LPC, lpc, dummy); + if (lpc & (1 << *irq)) + return -EIO; + + /* All chosen and checked - go for it */ + if (cs5535_mfgpt_toggle_event(timer, cmp, MFGPT_EVENT_IRQ, enable)) + return -EIO; + if (enable) { + zsel = (zsel & ~(0xF << shift)) | (*irq << shift); + wrmsr(MSR_PIC_ZSEL_LOW, zsel, dummy); + } + + return 0; +} +EXPORT_SYMBOL_GPL(cs5535_mfgpt_set_irq); + +struct cs5535_mfgpt_timer *cs5535_mfgpt_alloc_timer(int timer_nr, int domain) +{ + struct cs5535_mfgpt_chip *mfgpt = &cs5535_mfgpt_chip; + struct cs5535_mfgpt_timer *timer = NULL; + unsigned long flags; + int max; + + if (!mfgpt->initialized) + goto done; + + /* only allocate timers from the working domain if requested */ + if (domain == MFGPT_DOMAIN_WORKING) + max = 6; + else + max = MFGPT_MAX_TIMERS; + + if (timer_nr >= max) { + /* programmer error. silly programmers! */ + WARN_ON(1); + goto done; + } + + spin_lock_irqsave(&mfgpt->lock, flags); + if (timer_nr < 0) { + unsigned long t; + + /* try to find any available timer */ + t = find_first_bit(mfgpt->avail, max); + /* set timer_nr to -1 if no timers available */ + timer_nr = t < max ? (int) t : -1; + } else { + /* check if the requested timer's available */ + if (test_bit(timer_nr, mfgpt->avail)) + timer_nr = -1; + } + + if (timer_nr >= 0) + /* if timer_nr is not -1, it's an available timer */ + __clear_bit(timer_nr, mfgpt->avail); + spin_unlock_irqrestore(&mfgpt->lock, flags); + + if (timer_nr < 0) + goto done; + + timer = kmalloc(sizeof(*timer), GFP_KERNEL); + if (!timer) { + /* aw hell */ + spin_lock_irqsave(&mfgpt->lock, flags); + __set_bit(timer_nr, mfgpt->avail); + spin_unlock_irqrestore(&mfgpt->lock, flags); + goto done; + } + timer->chip = mfgpt; + timer->nr = timer_nr; + dev_info(&mfgpt->pdev->dev, "registered timer %d\n", timer_nr); + +done: + return timer; +} +EXPORT_SYMBOL_GPL(cs5535_mfgpt_alloc_timer); + +/* + * XXX: This frees the timer memory, but never resets the actual hardware + * timer. The old geode_mfgpt code did this; it would be good to figure + * out a way to actually release the hardware timer. See comments below. + */ +void cs5535_mfgpt_free_timer(struct cs5535_mfgpt_timer *timer) +{ + kfree(timer); +} +EXPORT_SYMBOL_GPL(cs5535_mfgpt_free_timer); + +uint16_t cs5535_mfgpt_read(struct cs5535_mfgpt_timer *timer, uint16_t reg) +{ + return inw(timer->chip->base + reg + (timer->nr * 8)); +} +EXPORT_SYMBOL_GPL(cs5535_mfgpt_read); + +void cs5535_mfgpt_write(struct cs5535_mfgpt_timer *timer, uint16_t reg, + uint16_t value) +{ + outw(value, timer->chip->base + reg + (timer->nr * 8)); +} +EXPORT_SYMBOL_GPL(cs5535_mfgpt_write); + +/* + * This is a sledgehammer that resets all MFGPT timers. This is required by + * some broken BIOSes which leave the system in an unstable state + * (TinyBIOS 0.98, for example; fixed in 0.99). It's uncertain as to + * whether or not this secret MSR can be used to release individual timers. + * Jordan tells me that he and Mitch once played w/ it, but it's unclear + * what the results of that were (and they experienced some instability). + */ +static void __init reset_all_timers(void) +{ + uint32_t val, dummy; + + /* The following undocumented bit resets the MFGPT timers */ + val = 0xFF; dummy = 0; + wrmsr(MSR_MFGPT_SETUP, val, dummy); +} + +/* + * Check whether any MFGPTs are available for the kernel to use. In most + * cases, firmware that uses AMD's VSA code will claim all timers during + * bootup; we certainly don't want to take them if they're already in use. + * In other cases (such as with VSAless OpenFirmware), the system firmware + * leaves timers available for us to use. + */ +static int __init scan_timers(struct cs5535_mfgpt_chip *mfgpt) +{ + struct cs5535_mfgpt_timer timer = { .chip = mfgpt }; + unsigned long flags; + int timers = 0; + uint16_t val; + int i; + + /* bios workaround */ + if (mfgpt_reset_timers) + reset_all_timers(); + + /* just to be safe, protect this section w/ lock */ + spin_lock_irqsave(&mfgpt->lock, flags); + for (i = 0; i < MFGPT_MAX_TIMERS; i++) { + timer.nr = i; + val = cs5535_mfgpt_read(&timer, MFGPT_REG_SETUP); + if (!(val & MFGPT_SETUP_SETUP)) { + __set_bit(i, mfgpt->avail); + timers++; + } + } + spin_unlock_irqrestore(&mfgpt->lock, flags); + + return timers; +} + +static int __init cs5535_mfgpt_probe(struct pci_dev *pdev, + const struct pci_device_id *pci_id) +{ + int err, t; + + /* There are two ways to get the MFGPT base address; one is by + * fetching it from MSR_LBAR_MFGPT, the other is by reading the + * PCI BAR info. The latter method is easier (especially across + * different architectures), so we'll stick with that for now. If + * it turns out to be unreliable in the face of crappy BIOSes, we + * can always go back to using MSRs.. */ + + err = pci_enable_device_io(pdev); + if (err) { + dev_err(&pdev->dev, "can't enable device IO\n"); + goto done; + } + + err = pci_request_region(pdev, MFGPT_BAR, DRV_NAME); + if (err) { + dev_err(&pdev->dev, "can't alloc PCI BAR #%d\n", MFGPT_BAR); + goto done; + } + + /* set up the driver-specific struct */ + cs5535_mfgpt_chip.base = pci_resource_start(pdev, MFGPT_BAR); + cs5535_mfgpt_chip.pdev = pdev; + spin_lock_init(&cs5535_mfgpt_chip.lock); + + dev_info(&pdev->dev, "allocated PCI BAR #%d: base 0x%llx\n", MFGPT_BAR, + (unsigned long long) cs5535_mfgpt_chip.base); + + /* detect the available timers */ + t = scan_timers(&cs5535_mfgpt_chip); + dev_info(&pdev->dev, DRV_NAME ": %d MFGPT timers available\n", t); + cs5535_mfgpt_chip.initialized = 1; + return 0; + +done: + return err; +} + +static struct pci_device_id cs5535_mfgpt_pci_tbl[] = { + { PCI_DEVICE(PCI_VENDOR_ID_NS, PCI_DEVICE_ID_NS_CS5535_ISA) }, + { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_CS5536_ISA) }, + { 0, }, +}; +MODULE_DEVICE_TABLE(pci, cs5535_mfgpt_pci_tbl); + +/* + * Just like with the cs5535-gpio driver, we can't use the standard PCI driver + * registration stuff. It only allows only one driver to bind to each PCI + * device, and we want the GPIO and MFGPT drivers to be able to share a PCI + * device. Instead, we manually scan for the PCI device, request a single + * region, and keep track of the devices that we're using. + */ + +static int __init cs5535_mfgpt_scan_pci(void) +{ + struct pci_dev *pdev; + int err = -ENODEV; + int i; + + for (i = 0; i < ARRAY_SIZE(cs5535_mfgpt_pci_tbl); i++) { + pdev = pci_get_device(cs5535_mfgpt_pci_tbl[i].vendor, + cs5535_mfgpt_pci_tbl[i].device, NULL); + if (pdev) { + err = cs5535_mfgpt_probe(pdev, + &cs5535_mfgpt_pci_tbl[i]); + if (err) + pci_dev_put(pdev); + + /* we only support a single CS5535/6 southbridge */ + break; + } + } + + return err; +} + +static int __init cs5535_mfgpt_init(void) +{ + return cs5535_mfgpt_scan_pci(); +} + +module_init(cs5535_mfgpt_init); + +MODULE_AUTHOR("Andres Salomon <dilinger@collabora.co.uk>"); +MODULE_DESCRIPTION("CS5535/CS5536 MFGPT timer driver"); +MODULE_LICENSE("GPL"); |
